So in a hurry out the door yesterday, I set my helmet down in a plastic-covered bed in the hospital while I adjusted my jacket armor. The plastic was slippery, the bed was at a tiny bit of an angle, and off it went; THUNK! four feet down to the hard hospital floor. There's no apparent damage, but the conventional wisdom is that if you drop your helmet, you need to replace it, as the foam interior may have compressed under the impact.
I wish there was some way to tell for sure whether anything's happened; it wasn't a hard impact, but it may have been hard enough. I'm not looking forward to the expense of a new lid, but it's my melon we're talking about protecting, so I suppose I'll bite the bullet and replace it. By and large I've been happy with this helmet (an HJC) but I've heard really good things about some of the Scorpions. Maybe I'll see how they feel...